EM 408S GPS Moduel quit

Well it appears that the 408 GPS engine bit the dust. Not sure if this is connected to my failed attempt to make a dual boot system. It was working after I reloaded windows and now has quit. I called GLobalSat great tech support but in the end no help.
I down loaded SiRF Demo from their web site and tried to reset factory settings on the engine. It is putting out NMEA data flow but does not ever get a fix. Nothing reads it, winfast, streets and trips, SiRF Demo. So I have pulled it out and gonna wait a few days to let the circuitry discharge and see if it resets it self. I pulled it out and can get a voltage reading, started at 3.3 held meter on it and watch the voltage drop to .6, then shorted pins and watch voltage drop to 0. Let sit for a few minutes and voltage climbed back up over 2! They must have some great capacitors in there! Will let it sit over night and see if it drains and then retry, otherwise I will just order a new one.
May just be my luck the way this week is going so far!
Rick H...

 

They do have a backup battery in there, which may explain the voltage.

I can't think of anything that could cause that. Did you tamper with any settings in SirfDemo?

 

Yes I did per the support lines direction. I can switch it to NMEA mode and see the data flow $G and some other info, but no fix and other programs do not even read that.
This morning the voltage was down to 1.6 so will se eif it drops more today.
Rick H...

 

I was having the same problem, then while trying to fix the problem or determine the problem, I was wiggling the wires going from EM408 to the rim card and notice one was hanging on by a single fine wire... not sure if this was the source of the problem, ordered a second new EM408...
Now when I have a chance, I am going to re solder the Rim card and compare the two cards on an external GPS antenna via SMA adapter. I will let you know what I find.

I think it may have been some settings too, because I was messing around with command line stuff (switching from NMEA to SIRF before I screwed it up. It is still a mystery to me - exact same symptoms as you have....NMEA data streaming....but no fix. I also thought it might have been the antenna, so I tried getting a lock with laptop upside down and battery out....no luck. So I ruled out the antenna as source of problem. (Since then I have damaged lcd GPS antenna, luckily I have a spare (Thank you TOUGHBOOK!)

If after re soldering the rim card, and both 408's test ok, I will know if draining the battery solution may have solved programming errors. And I will have a spare EM408!

Currently running GPS via SERIAL on RAM MOUNT / TOUGH DOCK! (Bluetooth GPS as another backup source!)

In fact I may abandon the EM408 GPS and patch hole on LCD, just need a corner cover. So I may have 2 spare 408's for sale,

 

If you verify that all 5 wires to the RIM board have continuity then check your center conductor on the antenna. See if the center lead runs to ground. A grounded center conductor on the antenna shows the same signs you describe.

 

Who has been using their 408s the longest? Daily use I mean... any issues so far? I just got my module yesterday, haven't had time to get it wired up to the daughter card yet. I'd hate to see a reliability problem with them! If it's just a question of the cable (or circuit board socket mounts) and any associated wiring we can solve those issues. I'm going to pull the useless metal brackets from the daughter card tonight and start soldering up some ribbon cable later this week if I'm lucky. I can't wait to get a working gps into my CF28 project book.

Thanks

 

All the above checked out fine. Nothing loose no shorts to ground including the antenna connector. Well other than the ground wire from the 408 connector.
I think its a setting that got changed on board the 408. Just can not think of what would have done it.
The voltage on the engine is dropping, down to less than .025 so over night should finish it off. Then I will reinstall and see what happens. if that does not do, I will order a new one and ask about warranty.
Thanks for the input.
Rick H...

 

Rich... Make sure you are reading zero before firing it back up. Now that I think about it... Someone else had this issue. They were playing around with the GPS program and fed some bad data to the engine. They drained the capacitor in the GPS and it worked fine after that.

 

Yeah I bought a GlobalSat 337 PCMCIA GPS. I loaded the software into my Wife's laptop, and, following the on screen prompts, I plugged in the device itself. Well, it immediately blue screened my Wife's laptop. A very serious aw shucks situation.

Long story short, I called the support section of GlobalSat and they told me to leave the card unplugged (not in the computer) for thirty (30) days and then retry it. You guys know my sick sense of humor; use your own imagination about my reply.

I tried it in my own laptop right after it BSOD'd my Wife's LT, and it worked fine, and has every since.

The moral of the story is never try new stuff in your Wife's LT unless you can say with complete confidence and a straight face; "gee honey, that's really strange, I sure wish knew how that happened, I'll look into it tomorrow."

 

That's why I don't have a wife, and avoid having girlfriends...

Toughbook had a good answer... It reminded me of a problem I had with an antenna cable. The module worked great, and everything showed signs of operation (Didn't pick up satellites, but I didn't go outside with it, just a quick power up to test). I soldered a cable onto a Geohelix antenna, attached it, and I got nothing. It shorted my unit out.

I can't remember what I did to test before disconnecting my antenna (I thought I gave the board a static shock), but I tested voltage with it on and it wasn't right.

On a side note, I crash XP every time I've got a USB GPS unit plugged in and is being "used" when I wake it up from sleep. (Ie; If I'm using Streets and Trips, close the lid, then open it up, I've got a crash, but only with USB GPS, not with the internal).

 

Thats what I am waiting on, the voltage to go away. I read that on another forum but can not recall where right now.
I don't think it would take 30 days though. I short the pins and the voltage goes to zero but only for a few seconds at a time. Caps can power a long time!
I was down to .022 tonight so I will try and hook it back up tomorrow night and see if it goes, if not, I am ordering a replacement and try and turn this one in for warranty. I am gonna need it for an up coming trip.
Rick H...

 

Rich... I just posted this in the Stickied GPS thread.... A thought I had today while soldering RIM boards for GPS'

*****************************************************
Something to add to this thread has struck me as I have been soldering a bunch of RIM boards with the 5-wire GPS leads...

Are you guys making sure that you have some sort of insulation between your RIM card and the magnesium base of the laptop? I'm thinking... If a laptop took a whack while on (and of course the GPS will be powered on as well) that there might be some sort of short between the solder points on the bottom of the card (or another of the small electrical components) and the magnesium case... Thereby shorting out something. As a precaution you should either use a fine layer of electrical tape on the bottom of the card for insulation or, if you are lucky enough, leave the black vinyl layer in there from the RIM setup.

Just a thought that hit me when I was soldering... Just wanted to post it.

*************************************************
Check yours... If you KNOW you have the vinyl sheet below the RIM board then it is not what the problem is... But this is something worth checking out for everyone!

Rick

 

Yep its there as mine had the RIM board. In addition, I used hot glue under the GPS engine so it sits up off the daughter board but still does not interfere with the battery.
Well put it back and it it is now working.
I used SiRF demo and just kept doing hardware resets and clear battery backed up ram option.
SiRF still was not reading it, I went to Navigator and it took right off.
Guess I fumbled some settings somewhere and between letting it sit out for 3 days and the voltage dropping down to .66 and then doing the resets, it came back to life.
By the way, hot glue works great. Holds well and comes off both the GPS metal housing and the daughter board with little effort and no damage.
Rick H...
Always an adventure!
Rick H...

 

Yes! The hot glue works wonders! I just finished runing a bead of hot glue on 8 of the RIM boards I fabbed up this evening. You can tug all you want... The wires will not pull off/twist, break, etc. BUT... If you need to take it off.... It will peel right off. Gotta love hot glue!

 

Hiya!

Nice to see someone talking about the EM - 408

I'm about to launch this GPS module in a rocket perhaps, or a ballon but the mainproblem is the external antenna. How do I know it's on? The module works perfectly after having almost the same problems as most of you. But now when it's working i'm getting signals and have no problem with sending commands to the gps.

Does the external antenna get activeted automaticly when I plugg the external antenna into the MMCX plug or do I have to enable it, and turn of the internal one?

Cheers Remi